This invention relates o line brake mechanisms and more particularly to line braking devices for, but not limited to, use in lowering people or objects from buildings.
In buildings that lack an elaborate indoor or outdoor fire escape stairway, or in situations where the entrance to these escape routes may be blocked by fire or smoke, a manually controlled line brake-type fire escape device can be useful. These devices can normally be connected to any solid fixture inside or just outside the room from which escape is desired, and are controlled variously by a person remaining in the room, a person on the ground, or by the person escaping. It is desirable that these devices have a wide range of braking adjustments so that the speed of descent can be controlled smoothly.
There has been a long standing need for improved line brake controlled fire escapes. Prior to this invention the use of this type of device for descents from heights of over four stories was unsafe. The main problem with the prior devices is that the frictional force needed to slow the descent of the escapee is developed between the line and the device itself. Because of this friction and the small size of the devices, heat is generated faster than it can be dissipated, leading to a sharp rise in temperature. The portions of the device which are in contact with the line eventually become hot enough to destroy the line or fail.
Accordingly, it is a specific aim of this invention to introduce a manually operable line brake device capable of providing a wide continuous range of frictional force adjustments without the disastrous failure problem noted above.